Panasonic Switch ASCT1F46E User Manual

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Panasonic Electric Works

Obihiro Co., Ltd.

Automotive Relay User’s Guide

Oct. 1, 2008: 1^stEdition

Please use the check sheet.

Category Section

1. Confirmation 1. Confirmation The rated switching power and life mentioned in the specification and catalog are given only as guides. A

Contents

under the

actual use

condition

under the

actual use

relay may encounter a variety of ambient conditions during actual use resulting in unexpected failure.

Therefore, it is necessary for proper use of the relay to test and review with actual load and actual

application under actual operating conditions.

2. Safety

1. Specification Use that exceeds the specification ranges such as the coil rating, contact rating and switching life should

precautions

range

be absolutely avoided. Doing so may lead to abnormal heating, smoke, and fire.

2. Installation,

Never touch live parts when power is applied to the relay. Doing so may cause electrical shock. When

maintenance installing, maintaining, or troubleshooting a relay (including connecting parts such as terminals and

sockets), be sure that the power is turned off.

3. Connection

When connecting terminals, please follow the internal connection diagrams in the catalog to ensure that

connections are done correctly. Be warned that an incorrect connection may lead to unexpected

operation error, abnormal heating, and fire.

4. Fail-safe

1. Selection

If there is a possibility that adhesion, contact failure, or breaking of wire could endanger assets or human

life, please make sure that a fail-safe system is equipped in the vehicle.

3. Selection of

relay type

In order to use the relays properly, the characteristics of the selected relay should be well known, and the

conditions of use of the relay should be investigated to determine whether they are matched to the

environmental conditions, and at the same time, the coil specification, contact specification, and the

ambient conditions for the relay that is actually used must be fully understood in advance.

In the table below, please refer to a summary of the consideration points regarding selection of relay.

Items

Consideration points regarding selection

a) Rating

b) Pull-in voltage

(current)

c) Drop-out voltage

(current)

- Select relay with consideration for power source ripple.

- Give sufficient consideration to ambient temperature

and for the coil temperature rise, and hot start.

- When used in conjunction with semiconductors, careful

with the voltage drop.

Coil

d) Maximum continuous - When starting up, careful with the voltage drop.

impressed voltage

(current)

e) Coil resistance

f ) Temperature rise

- Note that the relay life is balanced with the life of the

device the relay is used in.

a) Contact arrangement - Is the contact material matched to the type of load? It is

b) Contact rating

c) Contact material

d) Life

necessary to take care particularly with low level usage.

- The rated life may become reduced when used at high

temperatures. Life should be verified in the actual use

atmosphere.

Contact

e) Contact resistance

- It is necessary to be tested and reviewed under actual

use conditions with actual load and actual application.

- Note that ambient temperature and applied voltage

cause the change of operate time and bounce time.

- Note that operate time and release time do not include

bounce time.

a) Operate time

b) Release time

c) Bounce time

Operate time

d) Switching frequency

- Give consideration that switching life changes

depending on switching frequency.

a) Vibration resistance

b) Shock resistance

c) Ambient use

temperature

- Give consideration to performance under vibration and

shock in the use location.

- Confirm the allowable ambient temperature of the relay.

Mechanical

characteristics

d) Life

- Selection can be made for connection method with

plug-in type, printed circuit board type, soldering, and

screw fastening type.

- Selection of protection construction can be made for

PCB mounting method such as soldering and cleaning.

- For use in an adverse atmosphere, sealed construction

type should be selected.

a) Breakdown voltage

b) Mounting,

Connection

c) Size

d) Protection

construction

Other items

- Are there any special conditions?

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Contact performance is significantly influenced by voltage and current values applied to the contacts (in

particular, the voltage and current waveforms at the time of application and release), the type of load,

frequency of switching, ambient atmosphere, contact switching speed, and of bounce, which lead the

various other damages such as unsuitable operation contact transfer, welding, abnormal wear, increase

in contact resistance. Therefore, please confirm that in actual use conditions such as actual circuit and

actual load or contact our company.

4. Load,

Electrical life

1. General

2. Inductive

load

In the case of switching on and off with inductive loads such as coil, magnet crutch, and solenoid, the arc

at switching can cause a severe damage on contacts and greatly shortening of life. In addition, in the

case of switching at a high frequency, a blue-green corrosion may be developed. So, please contact our

company to use it.

If the current in the inductive load is relatively small, the arc discharge decomposes organic matter

contained in the air and causes black deposits (oxides, carbides) to develop on the contacts. This may

result in contact failure. So, please contact our company to use it.

3. Lamp load

Large inrush current enhancing contact welding will be impressed. Its current value is greatly affected by

wiring resistance, switching frequency and ambient temperature. The load current characteristics in

actual circuit and actual use condition must be examined and sufficient margin of safety must be

provided in selection of a relay.

It is dangerous to use a lamp load whose nominal current is small even a large nominal current has been

tested beforehand.

Please contact us when switching at nominal current with a small lamp load (40W or less), because

continuous ON failure may occur due to locking caused by contact-transfer phenomenon when switching

arc is locally concentrated.

4.Electric-

discharge

lamp load

5. LED lamp

load

Its load current tends to cause contact welding easily because its inrush current is larger than that of the

regular lamp load. The load current characteristics in actual circuit and actual use condition must be

examined and sufficient margin of safety must be provided in selection of a relay.

It is necessary to check the contact reliability because the load current of the LED load is very small.

Please contact us before use.

6. Other lamp

load

Please contact us before use of new structured lamp except for halogen, Electric-discharge lamp, and

LED.

7. Motor load

When using of NC contact side of 1C contact for the motor brake, mechanical life might be affected by

the brake current. Therefore, verify in actual use conditions with actual circuit.

Note that larger inductivity of motor may cause contact damage and transfer even the motor load current

is same.

8. Capacitor

load

Note that its load current tends to cause contact welding and contact transfer easily because its inrush

current is generally large which has a small break current and a short time period to reach an inrush

peak value.

Also, inrush current value is influenced by wiring resistance. Therefore, the inrush current in actual circuit

must be examined and sufficient margin of safety must be provided in selection of a relay.

This load causes relatively-less contact damage since its inrush current is not large. Select a relay based

on the rating control capacity, or contact us.

9. Resistance

load

10. Small

electric

current

If the switching current is small (2A or less), contact reliability decreases since the contact surface is not

cleaned by switching arc. So, please contact us for use.

load

11. Load

polarity

Electrical life may be affected by load polarity (+/-) connecting to relay contacts. So, please verify them in

actual use polarity.

12. Voltage

drop of

Under a circuit which inrush current is applied to such as lamps and capacitors, the moment the contact

is closed, voltage drop to the coil, return of relay, or chattering may occur. Note that it may remarkably

reduce the electrical life.

power

supply

Load

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4. Load,

Electrical

life

13. Load

voltage

If the load voltage is high, the arc energy which generated at contact switching increases, which may

decrease the electrical life. Therefore, it is necessary to give consideration to the voltage which could

occur in actual use condition.

14. Coil voltage If coil applied voltage gets higher, the relay operate time gets faster. However, contact bounce gets also

larger so that the electrical life may decrease.

15. Coil

short-pulse

When the short-pulse signal is input to the relay coil, the relay movable part may operate and touch

lightly to the contact. Therefore, please avoid short pulse input (100ms or less) since it may cause

contact welding due to less contact pressure. Please test adequately, for example when a relay is

operated by external manual switch (such as key switch.)

input

16. High-

When the switching frequency is high, the electrical life may decrease. Please confirm if there is a

high-frequent switching caused by abnormal mode in actual use condition.

frequency

of switching

17. Low-

Note that if the contact has not been switched for a long time period, organic film tends to be generated

on the contact surface, which may cause contact instability.

frequency

of switching

18. Ambient

temperature

Verify in the actual use condition since electrical life may be affected by use at high temperatures.

19. Connection If resistor, diode, zener diode are connected parallel to decrease the surge voltage when the relay coil

of coil surge

absorption

circuit

being turned off, the relay release time will get longer and may decrease the electrical life or cause

light-welding.

Load

20. Sneak or

remaining

current

Please test a relay in actual vehicle condition since there is a risk of deterioration at relay function or

switching performance such as slower release time which is caused by sneak current due to diode,

zener diode, capacitor mounted on a vehicle or by remaining current soon after a motor is turned off.

21. Wire length If long wires (a few ten meters) are to be used in a relay contact circuit, inrush current may become a

problem due to the stray capacitance existing between wires. In such case, add a resistor in series with

the contacts.

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4. Load,

electrical life

22. Contact

protective

circuit

Use of contact protective devices or protection circuits can suppress the counter emf to a low level.

However, note that incorrect use will result in an adverse effect. Typical contact protection circuits are

given in the table below.

Also, note that release time will slow down due to sneak in the circuit and may cause the electrical life to

shorten and slight-welding.

Diode circuit

Circuit

The diode connected in parallel causes the energy stored in the coil

to flow to the coil in the form of current and dissipates it as joule

Features/Others

Devices Selection

heat at the resistance component of the inductive load. This circuit

delays the release time. (2 to 5 times the release time listed in the

catalog)

Use a diode with a reverse breakdown voltage at least 10 times the

circuit voltage and a forward current at least as large as the load

current or larger.

In electronic circuits where the circuit voltages are not so high, a

diode can be used with a reverse breakdown voltage of about 2 to 3

times the power supply voltage.

Diode and zener diode circuit

Circuit

Features/Others

Devices Selection

It is effective in the diode circuit when the release time is too long.

Use a zener diode with a zener voltage about the same as the power

supply voltage

In the actual circuit, it is necessary to mount the protective device (diode etc.) in the immediate vicinity of

the load. If it is mounted too far away, the effectiveness of the protective device may diminish. As a guide,

the distance should be within 50cm.

Avoid using the protection circuits shown in the figures below.

Although it is usually more difficult to switch with DC inductive loads compared to resistive loads, use of

the proper protection circuit will raise the characteristics to that for resistive loads.

Although it is extremely effective in arc

suppression as the contacts open, the

contacts are susceptible to welding since

Although it is extremely effective in arc

suppression as the contacts open, the

contacts are susceptible to welding since

energy is stored in C when the contacts open charging current flows to C when the

and discharge current flows from C when the contacts close.

contacts close.

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4. Load,

electrical

23. Connection Connect the load to one side of the power supply as shown in Fig. (a). Connect the contacts to the other

of load

side. This prevents high voltages from developing between contacts. If contacts are connected to both

side of the power supply as shown in Fig. (b), there is a risk of shorting of the power supply when

relatively close contacts short.

life

Fig. (a) Good example

(b) Bad example

Regarding the following circuit constructions with 2-coil relays (twin relays) or single-pole relays, an arc

between contacts may be generated when breaking of load current depending on the type of load

current, voltage, and load. Please note that or contact us.

＜2 coil relay (twin relay) or two of single-pole relays＞

Short current

Arcing

Ａ

B side OFF

Load

＜Single-pole relay＞

Load

Arcing

Load

OFF

24. Short

between

When using of multipole relays such as 2-coil relays (twin relays), verify insulation and breakdown

voltage between contacts in each pole in order to avoid an accident caused by short.

interelectrodes

1. Hot start

voltage

5. Coil

impressed

voltage

After continuous applying of current to coil and contacts, if the current is turned OFF then immediately

turned ON again, coil resistance and the pick-up voltage will increase due to the temperature rise in the

coil.

Temperature rise value of coil is greatly affected by circuit board, connected harness, connected

connector, heat dissipation of system/modules, and heat source around relay. Please verify whether it is

operating properly or inoperative under actual vehicle and actual use conditions.

Coil resistance and the pick-up voltage will increase when the relay is used in a higher temperature

atmosphere. The resistance/temperature coefficient of copper wire is about 0.4% for 1°C, and the coil

2. Ambient

temperature

characteristic resistance increases with this ratio. On the other hand, coil resistance and the drop-out voltage will

decrease at lower temperature. Coil resistance change decreases with the same ratio at higher

temperature, about 0.4% for 1°C.

Therefore, please confirm the relay operation in every operating temperature range, with attention to

such temperature characteristic.

The ambient usage temperature should be set as around the relay inside the box because a heat

generated by a relay itself or other instruments causes increase of temperature inside the box.

3. Applied

voltage

Note that a coil impression with a voltage greater than or equal to the maximum continuous impressed

voltage may cause temperature rise which could cause coil burning or layer short. Furthermore, do not

exceed the usable ambient temperature range listed in the catalog. Please contact us regarding PWM

control.

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For relays which have multiple coils such as twin relay for forward-reverse operation of motor, if the coils

are continuously turned on at the same time, the coil temperature may exceed the tolerance in a short

5. Coil

impressed

voltage

4.Twin-relay

coil

simultaneous time due to heat generation of each coil. Please contact us before use.

operation

5. Continuous

current

Coil heating due to continuous current applying to coil for extensive time periods will cause deterioration

in insulation performance for coil.

For such circuit types, please consider the fail-safe circuit design in case of contact failure or breaking of

coil.

6. Coil

1. Relay drive

1. Connection method

impressed

circuit

by means of Collector connection method is the most recommendable when the relay is driven by means of a

a transistor

transistor.

To avoid troubles in use, the rated voltage should always be impressed on the relay in the ON time and

zero voltage be done in the OFF time.

(Care) Parallel connection

As the power consumption of

the entire circuit increases,

the relay voltage should be

considered.

(Care) Emitter connection

When the circumstances make

the use of this connection

unavoidable, the voltage may not

be completely impressed on the

relay and the transistor would not

conduct completely.

(Good) Collector connection

This is the most common

connection, which operation is

usually stable with.

2. Countermeasures for surge voltage of relay control transistor

If the coil current is suddenly interrupted, a sudden high voltage pulse is developed in the coil. If this

voltage exceeds the breakdown voltage of the transistor, the transistor will be degraded, and this will

lead to damage. It is absolutely necessary to connect a diode in the circuit as a means of preventing

damage from the counter emf. In case of DC relay, connection of Diode is effective. As suitable ratings

for this diode, the average rectified current should be equivalent to the coil current, and the reverse

blocking voltage should be about 3 times the value of the power source voltage. Connection of a diode is

an excellent way to prevent voltage surges, but there will be a considerable time delay when the relay is

open. If you need to reduce this time delay you can connect between the transistor's Collector and

Emitter with a Zener diode that will make the Zener voltage somewhat higher than the supply voltage.

Diode

Take care of Area of Safe Operation (ASO).

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6. Coil

impressed

circuit

1. Relay drive

3. Snap action (Characteristic of relay with voltage rise and fall)

by means of It is necessary for the relay coil not to impress voltage slowly but to impress the rated voltage in a short

a transistor

time and also to drop the voltage to zero in a short time.

Non-pulse signal

Pulse signal (square wave)

(No good) Without snap action

(Good) Snap action

4. Schmitt circuit (Snap action circuit) (Wave shaping circuit)

When the input signal does not produce a snap action, ordinarily a Schmitt trigger circuit is used to

produce safe snap action.

1. The common emitter resistor R_Emust have a sufficiently small value compared with the resistance of

the relay coil.

2. Due to the relay coil current, the difference in the voltage between at point P when T₂is conducting and

at point P when T₁is conducting creates hysteresis in the detection capability of Schmitt circuit, and care

must be taken in setting the values.

3. When there is chattering in the input signal because of waveform oscillation, an CR time constant

circuit should be inserted in the stage before the Schmitt trigger circuit. (However, the response speed

drops.)

5. Avoid Darlington circuit connections. (High amplification)

Care must be taken in this circuit due to increase of V_CESAT. It does not cause a failure immediately, but it

may lead to troubles by using for a long period or by operating with many units.

（No good） Darlington connection

Due to excessive consumption of

power, heat is generated.

(Good) Emitter connection

Tr2 conducts completely.

Tr1 is sufficient for signal use.

A strong Tr1 is necessary.

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6. Coil

impressed

circuit

1. Relay drive

6. Residual Coil Voltage

by means of In switching applications where a semiconductor (transistor, UJT, etc.) is connected to the coil, a residual

a transistor

voltage is retained at the relay coil which may cause incomplete restoration and faulty operation. Using

of DC coils may cause incomplete restoration or reduction in contact pressure and vibration resistance,

because its drop-out voltage is lower than that of AC coil (10% or more of the rated voltage) also

because there is a tendency to increase the life by lowering the drop-out voltage.

When the signal from the transistor's collector is taken and used to drive another circuit as shown in the

figure as follows, a minute dark current flows to the relay even if the transistor is off. This may also cause

the problems described above.

Connection to the next stage through collector

2. Relay drive

1. Ordinary drive method

by means of For SCR drive, it is necessary to take particular care with regard to gate sensitivity and erroneous

SCR operation due to noise.

I_GT: There is no problem even with more than 3 times

the rated current.

R_GK: 1K ohms must be connected.

RC : This is for prevention of switching error due to a

sudden rise in the power source or to noise.

2. Cautions regarding ON/OFF control circuits

(when used for temperature control circuits or similar one)

Care must be taken because the electrical life suffers extreme shortening when the relay contacts close

simultaneously with an AC single phase power source.

1. When the relay is turned ON and OFF using a SCR, the SCR serves as a half wave power source as it

is, and there are ample cases where the SCR is easily restored.

2. In this manner the relay operation and restoration timing are easily synchronized with the power

source frequency, and the timing of the load switching also is easily synchronized.

3. In case of the load for temperature control whose load is a high current load such as a heater, some

relays switch only peak values and some other relays switch only zero phase values as a phenomenon

of this type of control. (Depending upon the sensitivity and response speed of the relay)

4. Accordingly, it causes either an extremely long life or an extremely short life resulting in wide variation.

So, it is necessary to take care with the initial device quality check.

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７. Contact

1. Load switch When switching with a very small load after switching with a large load, “contact failure by small load

reliability

switching” may occur due to particles generated during switching of the contact with large load. Please

note that or contact us.

2. Installation

condition

Note that if it is connected or installed with a high heat-capacity such as bas bar, connector, harness,

and PCB, heat removal phenomenon at low temperature will make relay terminals and contacts cool and

condensate a small amount of organic gas inside the relay, which may cause a contact failure. So,

please contact us before use.

8. Contact

resistance

1. Transient

state

Contact resistance consists of dynamic and static contact resistance. “Contact resistance” on the

catalogue and the specifications refers to static contact resistance. Dynamic contact resistance usually

shows a large value due to just after the contact operation. Please contact us if a stable contact

resistance is necessary soon after a relay is turned on.

2. Contact

voltage,

current

Note that if the contact-applied voltage is small (at 6V or less) and contact-applied current is small (at 1A

or less), contact resistance may become a larger value due to a small amount of film on a contact

surface.

9. Operate

noise

1. Coil applied Mechanical relays produce an operational noise at operate and release time. Note that if the coil-applied

voltage

voltage is higher at operate time, the noise becomes larger.

2. Operate

noise at

installation

It is necessary to test relays in actual installation condition because operate noise may become larger in

the installation condition than with a relay by itself due to resonance and sympathetic vibrations of

installation PCB and system module.

10.Mechanical

noise

1. Abnormal

noise

Note that if a large current is applied to the contact, electromagnetic repulsion makes contact vibrate and

produces an abnormal noise. Please contact us if quietness is required.

Note that if an external vibration and shock are applied to a relay while the relay turns off, a movable part

of the relay may vibrate and produce a noise. So, please test in the actual use condition if quietness is

required.

11. Electrical

noise

1. Serge

voltage

When the relay turns off, serge voltage is generated from the coil. This serge voltage can be reduced if a

resistor is connected in parallel to the coil. Likewise, it can be reduced more if a diode instead of resistor

is connected in parallel.

However, please contact us or note that if a resistor or a diode is connected in parallel electrical life may

be affected due to slowing down of release time.

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12. Usage

ambient

1.Temperature, During usage, storage, or transportation, avoid locations subject to direct sunlight and maintain normal

humidity,

temperature, humidity, and pressure conditions.

condition

air pressure

The allowable specifications for environments suitable for usage, storage, and transportation are given

below.

1. Temperature: The allowable temperature range differs with each relay, so refer to the relay's

individual specifications. In addition, in the case of transporting and storing relays in a tube package, the

temperature may differ from the allowable range of the relay. So, please contact us for individual

specifications.

2. Humidity: 5 to 85 % R.H.

3. Pressure: 86 to 106 kPa

Furthermore, the humidity range varies with the temperature. So, use relays within the range indicated in

the graph below.

(The allowable temperature range differs for each relay.)

-Be sure the usage ambient temperature does not exceed the value listed in the catalog.

-When switching with a load which easily generates arc in high-humidity environment, the NO_x

generated by the arc and the water absorbed from outside the relay combine to produce nitric acid.

This corrodes the internal metal parts and adversely affects operation. Avoid using them at an ambient

humidity of 85%RH or higher (at 20°C). If it is unavoidable to use them in such environment, please

consult us.

-Plastic sealed type relays are especially not suited for use in environments which require airtight relays.

Although there is no problem if they are used at sea level, avoid using them in atmospheric pressures

beyond 96±10kPa. Also avoid using them in an atmosphere containing flammable or explosive gases.

It is recommendable to use relays in a normal temperature and humidity with less dust, sulfur gases

(SO₂, H₂S), and organic gases.

2. Dust

Sealed types (plastic sealed type) should be considered for applications in an adverse environment.

Silicon-based substances (silicon rubber, silicon oil, silicon-based coating material, silicon caulking

compound, etc.) emit volatile silicon gas. Note that when silicon is used near relay, switching the

contacts in the presence of its gas causes silicon to adhere to the contacts and may result in contact

failure.

3. Silicon

Therefore, please use a substitute that is not silicon-based. Plastic also has air permeability so please

avoid using them in a silicone atmosphere.

4. Magnetism

5. Vibration

If relays are proximately installed each other or installed near highly-magnetized parts such as motor

and speaker, the relay may change its operational characteristics or cause malfunction. So, please

verify in actual installation and operational condition.

Vibration of the area where relay is installed may be enhanced more than expected depending on

installation condition of PCB. So, please verify in actual use condition. NO contact is the recommended

contact for the use at the vibration-frequent area because the vibration resistance performance of NC

contact is generally inferior to that of NO contact.

6. Shock

It is ideal for mounting of relay that the movement of the contacts and movable parts is perpendicular to

the direction of vibration or shock. Especially note that the vibration and shock resistance of NC contacts

while the coil is not excited is greatly affected by the mounting direction of the relay.

Condensation forms when vapors when there is a sudden change in temperature under high

temperature, high humidity conditions. Note that condensation may cause deterioration of the insulation,

breaking of coil, and rusting.

7. Dew

condensation

Note that if a relay is connected or installed with a high heat-capacity such as bas bar, connector,

harness, and PCB, heat removal phenomenon will accelerate cooling of the relay inside and promote

condensation. So, please verify in actual installation condition.

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Select the sealed-type for exposure to water. In the case of water exposure in severe conditions or

immersion, please verify water resistance of the relay or contact us. Even for sealed-type relays, its

terminals are not waterproof, so please avoid a failure such as terminal corrosion.

12. Usage

ambient

8. Water

resistance

condition

9. Freezing

Note that moisture adhered on relay in a due condensation or a high humidity condition freezes when

the temperature is lower than 0°C. This may cause problems such as sticking of movable parts or

operational time lags, or poor contact conduction. Therefore, please test them in actual use

environment.

Note that if a relay is connected or installed with a high heat-capacity such as bas bar, connector,

harness, and PCB, heat removal phenomenon will accelerate cooling of the relay inside and promote

freezing. So, please verify in actual installation condition.

10. Low

The plastic becomes brittle if the relay is exposed to a low temperature, low humidity environment for

temperature, long periods of time.

low humidity

13.Installation

1. Connector

installation

Please consider the vibration at installation area to avoid loosely-contact.

Also, note that even a microscopic vibration may cause contact failure at the contact area of relay

terminal and connector.

Decrease of fitting performance of connector may cause abnormal heat at connector contact area

depending on use temperature and applying heat. Sufficient margin of safety must be provided in

selection of a connector.

Please select the proper material of connector and surface treatment to avoid corrosion at the contact

area of relay terminal and connector and increase of resistance at connecting area which may be

caused depending on ambient environment.

14. PC board

design

1. PC board

design

1. Cautions regarding Pattern Layout for Relays

consideration

Since relays affect electronic circuits by generating noise, the following points should be noted.

•

Keep relays away from semiconductor devices.

Design the pattern traces with the shortest length.

Place the surge absorber (diode, etc.) near the relay coil.

Avoid routing pattern traces susceptible to noise (such as for audio signals) underneath the

relay coil section.

•

Avoid through-holes in places which cannot be seen from the top (e.g. at the base of the

relay). Solder flowing up through such a hole may cause damage such as a sealing failure.

Even for the same circuit, it is necessary to consider the pattern design in order to minimize

the influence of the on/off operations of the relay coil and lamp on other electronic circuits, as

shown in the figure below.

-Relay coil currents consist only of A1 and B1.

-Electronic circuit currents consist only of A2

and B2. A simple design can change safety of

the operation.

-Relay currents and electronic circuit

currents flow together through A and B.

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14. PC board

design

2. Hole and

Land

diameter

The Hole and Land diameter are made with the hole slightly larger than the lead wire so that the

component may be inserted easily. Also, when soldering, the solder will build up in an eyelet condition,

increasing the mounting strength. The standard dimensions for the Hole diameter and Land are shown

in the table below.

Standard dimensions for the Hole and Land diameter

Unit: mm/ inch

Standard Hole

0.8/ .031

Tolerance

Land diameter

2.0 to 3.0/ .079 to .118

1.0/ .039

±0.1/ ±.039

1.2/ .047

3.5 to 4.5/ .138 to .177

1.6/ .063

Remarks

•

The Hole diameter is made 0.2 to 0.5mm/ .008 to .020inch larger than the lead diameter.

However, if the jet method (wave type, jet type) of soldering is used, solder may pass through

to the component side. Therefore, it is more suitable to make the Hole diameter equal to the

lead diameter +0.2mm.

•

The Land diameter should be 2 to 3 times the Hole diameter.

Do not put more than 1 lead in one hole.

3. Expansion

and

Because copper-clad laminates have a longitudinal and lateral direction, the manner of punching

fabrication and layout must be observed with care. Expansion and shrinkage in the longitudinal direction

due to heat is 1/15 to 1/2 of that in the lateral, and accordingly, after the punching fabrication, the

distortion in the longitudinal direction will be 1/15 to 1/2 of that in the lateral direction. The mechanical

shrinkage

copper-clad strength in the longitudinal direction is 10 to 15% greater than that in the lateral direction. Because of

laminates

this difference between the longitudinal and lateral directions, when products having long configurations

are to be fabricated, the lengthwise direction of the configuration should be made in the longitudinal

direction, and PC boards having a connector section should be made with the connector along the

longitudinal side.(The figure below)

Example: As shown in the drawing below, the 150mm (5.906 inch) direction is taken in the longitudinal

direction.

Also, as shown in the drawing below, when the pattern has a connector section, the direction is taken as

shown by the arrow in the longitudinal direction.

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15. PCB

mounting

1. Through-hole type

In keeping with making devices compact, it is becoming more common to solder the relay to a PC board along with the

semiconductors instead of using the previous plug-in type in which relays were plugged into sockets.

With this style, loss of function may occur because of seepage into the relay of flux, which is applied to the PC board. Therefore,

the following precautions are provided for soldering a relay onto a PC board. Please refer to them during installation in order to

avoid problems.

The type of protective structure will determine suitability for automatic soldering or automatic cleaning. Therefore, please review

the parts on construction and characteristics.

• Avoid bending the terminals to make

1. Mounting of Relay

the relay self-clinching. Relay

performance cannot be guaranteed if

the terminals are bent.

• Correctly make the PC board according

to the given PC board pattern

illustration.

• Tube packaging for automatic mounting

is available depending on the type of

relay. (Be sure that the relays don't

rattle.) Interference may occur internally

Bad example

if the gripping force of the tab of the

surface mounting machine is too great.

This could impair relay performance.

• Adjust the position of the PC board so

that flux does not overflow onto the top

of it. This must be observed especially

for dust-cover type relays.

2. Flux Application

• Use rosin-based non-corrosive flux.

• If the PC board is pressed down into a

flux-soaked sponge as shown on the

right, the flux can easily penetrate a

dust-cover type relay. Never use this

method. Note that if the PC board is

pressed down hard enough, flux may

even penetrate a flux-resistant type

relay.

Bad example

• Be sure to preheat before using

automatic soldering. For dust-cover

type relays and flux-resistant type

relays, preheating acts to prevent the

penetration of flux into the relay when

soldering. Solderability also improves.

• Preheat according to the following

conditions.

• Note that long exposure to high

temperatures (e.g. due to a

malfunctioning unit) may affect relay

characteristics.

3. Preheating

120°C/ 248°F or less

Temperature

(PCB solder surface)

Within approx. 2

minute

Time

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Automatic Soldering

Hand Soldering

4. Soldering

•

Flow solder is the optimum method for • Please take caution with multi-layer

soldering.

Adjust the level of solder so that it does

not overflow onto the top of the PC

board.

boards. Relay performance may

degrade due to the high thermal

capacity of these boards

• Keep the tip of the soldering iron

clean.

•

Unless otherwise specified, solder

under

the

following

conditions

depending on the type of relay.

Soldering Iron

Iron Tip

Temperature

30W to 60W

Approx. 350°C

Solder

Approx.260°C±5°C/

Within approx. 3

seconds

Temperature

500°F±41°F

Within approx. 6

seconds

Soldering Time

• Immediate air cooling is recommend to prevent deterioration of the relay and

surrounding parts due of soldering heat.

5. Cooling

• Although environmentally the sealed type relay (plastic sealed type, etc.) can be

cleaned, avoid immersing the relay into cold liquid (such as cleaning solvent and

coating material) immediately after soldering. Doing so may deteriorate the sealing

performance.

• Do not clean dust-cover type relays and flux-resistant type relays by immersion.

Even if only the bottom surface of the PC board is cleaned (e.g. with a brush),

careless cleaning may cause cleaning solvent to penetrate the relay.

• Plastic sealed type relays can be cleaned by immersion. Use an alcohol-based

cleaning solvent. Use of other cleaning solvents (e.g. Trichlene, chloroethene,

thinner, benzyl alcohol, gasoline) may damage the relay case.

6. Cleaning

• Cleaning with the boiling method is recommended. Avoid ultrasonic cleaning on

relays. Use of ultrasonic cleaning may cause breaks in the coil or slight sticking of

the contacts due to the ultrasonic energy.

• Do not cut the terminals. When terminals are cut, breaking of coil wire and slight

sticking of the contacts may occur due to vibration of the cutter.

• If the PC board is to be coated to prevent the insulation of the PC board from

deteriorating due to corrosive gases and high temperatures, note the following.

• Do not coat dust-cover type relays and flux-resistant type relays, since the coating

material may penetrate the relay and cause contact failure. Or, mount the relay

after coating.

7. Coating

• Depending on the type, some coating materials may have an adverse affect on

relays. Furthermore, some solvents (e.g. xylene, toluene, MEK, I.P.A.) may

damage the case or chemically dissolve the epoxy and break the seal. Select

coating materials carefully.

• If the relay and all components (e.g. ICs) are to be coated, be sure to carefully

check the flexibility of the coating material. The solder may peel off from thermal

stress.

Coating

material type

Suitability

for Relays

Features

Good electrical insulation.

Epoxy-base

Good

Although slightly difficult to apply, does not affect

relay contacts.

Good electrical insulation, easy to apply.

Solvent may damage case. Check before use.

Silicon gas becomes the cause of contact failure.

Do not use the silicon-base type.

Urethane-base

Silicon-base

Care

No Good

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15. PCB

mounting

2. SMD type

To meet the market demand for downsizing to smaller, lighter, and thinner products, PC boards also need to proceed from

insertion mounting to surface mounting technology.

To meet this need, we offer a line of surface mount relays. The following describes some cautions required for surface

mount relay installation to prevent malfunction and incorrect operation.

*Please contact us for or reflow soldering of through-hole terminal type.

1. What is a Surface Mount Relay?

1. From IMT to SMT

Conventional insertion mount technology (IMT) with some 30 years of history is now being replaced with surface mount

technology (SMT).

Solid-state components such as resistors, ICs, and diodes can withstand high heat stresses from reflow soldering because

they use no mechanical parts. In contrast, the conventional electro-mechanical relays consisting of solenoid coils, springs,

and armatures are very sensitive to thermal stress from reflow soldering.

We applied the experience gained from our advanced relay technologies to produce high-performance electromagnetic

relays compatible with surface mount technologies such as IRS and VPS.

Insertion Mount Technology & Surface Mount Technology

Insertion

Mounting

Technology

Components' terminals are inserted into terminal

holes of PC board and are soldered to copper pads

on the other side of the board. (flow-soldering)

(IMT)

Surface

Mounting

Technology

(SMT)

Chip resistor

Components are placed on copper pads pre-coated

with paste solder and the board assembly is heated to

solder the components on the pads. (reflow soldering)

2. Features and Effects

Features

Effects

Allows high density mounting

Components can be installed on both sides of a board

Ceramic PC boards can be used

System downsizing

Compatible with automatic placement by robots

Drilling for lead holes is not required

Compact system designs are possible due to high density mounting

Overall cost reduction

High reliability

High heat resistance

Anti-gas measures

The surface mount relay is realized with the following advanced technologies:

• Heat-resistance encapsulation technique

• Gas analysis

• Reliability assessment

• Precision molding technique for heat-resistant materials

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3. Examples of SMT Applications

IRS is the most popular reflow soldering technology now available for surface mounting. It

uses a sheath heater or infrared lamp as its heat source. PC board assemblies are

continuously soldered as they are transferred through a tunnel furnace comprised of a

preheating, heating, and cooling-stages.

1. Infrared Reflow Soldering

(IRS)

With VPS technology, PCB assemblies are carried through a special inactive solvent,

such as Fluorinert FC-70, that has been heated to a vapor state. As the saturated vapor

condenses on the PC board surface, the resulting evaporation heat provides the energy

for reflow soldering.

2. Vapor Phase Soldering (VPS)

As PCB assemblies are transferred on a thin, heat-resistant belt conveyer, they are

soldered by the heat from hotplates placed beneath the conveyer belt.

3. Belt conveyer reflow oven

After components are glued to the PC board surface, the board assembly is transferred

4. Double Wave Soldering (DWS) through a molten solder fountain (with the component side facing down). Then, the

components are soldered to the board.

Other reflow soldering technologies include those of utilizing lasers, hot air, and pulse

5. Other Technologies

heaters.

2. Cautions for installation

1. Paste Soldering

•

Mounting pads on PC boards

must be designed to absorb

placement errors while taking

account of solderability and

insulation. Refer to the

suggested mounting pad layout

in the application data for the

required relay product.

Paste solder may be applied on

the board with screen printing or

dispenser techniques. For either

method, the paste solder must

be coated to appropriate

thickness and shapes to

achieve good solder wetting and

adequate insulation.

2. Relay mounting

•

For small, lightweight components such as chip components, a

self-alignment effect can be expected if small placement errors exist.

However, this effect is not as expected for electro-mechanical components

such as relays, and they require precise positioning on their soldering pads.

If SMT relays are subjected to excessive mechanical stress from the

placement machine's pickup head and damaged inside, their performance

cannot be guaranteed.

•

Our SMT relays are supplied in tube packaging compatible with automatic

placement processes. We also offer tape packaging at customer request..

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3. Reflow

Reflow soldering under inadequate soldering conditions may result in unreliable

relay performance or even physical damage to the relay (even if the relay is of

surface mount type with high heat resistance).

1.IRS profile

Note: When a soldering technique other than above is to be used (hot air, hotplate,

laser, or pulse heater technique), carefully investigate the suitability of the

technique.

The soldering temperature profile indicates the pad temperature. In some

cases, the ambient temperature may be greatly increased. Examine it under

the specific mounting condition.

2.Manual soldering

Soldering iron tip temperature: 350°C (662°F)

Soldering iron wattage: 30 to 60 W

Soldering time: Less than 3 sec.

3.Others

For other solder methods except for the above (such as hot air heating, hot plate

heating, laser heating, pulse heating, etc.), please check for mounting and soldering

condition before use.

• It is recommended that the soldered pad be immediately cooled to prevent thermal

damage to the relay and its associated components.

• While surface mount relays are solvent washable, do not immerse the relay in cold

cleaning solvent immediately after soldering.

4. Cooling / Cleaning

• While sealed-type (plastic-sealed) relays are solvent washable, do not immerse

the relay in cold cleaning solvent immediately after soldering.

• Use alcohol or an equivalent solvent for cleaning.

• Boiled cleaning is approved for surface mount relays. Ultrasonic cleaning may

cause coil damage or light contact sticking.

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16. Soldering

1. Solder

Please use the flux-resistant type or sealed type in the case of automatic soldering.

2. Cleaning

Please use the sealed type for cleaning. Also, use the alcohol type for cleaning liquid and avoid

ultrasonic cleaning.

When cleaning a printed circuit board after soldering, we recommend using alcohol-type cleaning

liquid. Please avoid ultrasonic cleaning. The ultrasonic energy may cause breaking of coil and

sticking of contacts.

3. Terminal clinch

1.Transportation

Avoid bending terminals for the relay of print circuit board since it may cause malfunction.

17. Storage,

transportation

Relay’s functional damage may occur if strong vibration, shock or heavy weight is applied to a relay

during transportation of a device in which a relay is installed. Therefore, please pack them in a way,

using shock-absorbing material, so that the allowable range for vibration and shock is not exceeded.

If the relay is stored for extended periods of time (including transportation period) at high

temperatures or high humidity levels or in atmospheres with organic gas or sulfide gas, sulfide film or

oxide film may be formed on surface of the contacts, which may cause contact instability, contact

failure and functional failure. Please check the atmosphere in which the units are to be stored and

transported.

2. Storage

18. Product

handling

1. Tube packing

Some types of relays are supplied with tube packaging. If you remove some relays from the tube, be

sure to slide a stop plug into one end of a tube to hold the remaining relays firmly and avoid rattling of

relay inside the tube. Note that rattling may cause a damage on appearance and/or performance.

Do not use the relays if they were dropped or fallen down in a tube packing condition because there

is a risk of characteristic failure.

Fall of tube

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19. Reliability

[1] What is Reliability?

1. Reliability in a Narrow Sense of the Term

In the industrial world, reliability is an index of how long a particular product serves without failure during use period.

2. Reliability in a Board Sense of the Term

Every product has a finite service lifetime. This means that no product can continue normal service infinitely. When a product has broken

down, the user may throw it away or repair it. The reliability of repairable products is recognized as "reliability in a broad sense of the

term." For repairable products, their serviceability or maintainability is another problem. In addition, reliability of product design is

becoming a serious concern for the manufacturing industry. In short, reliability has three senses: i.e. reliability of the product itself,

serviceability of the product, and reliability of product design.

3. Intrinsic Reliability and Reliability of Use

Reliability is "built" into products. This is referred to as intrinsic reliability which consists mainly of reliability in the narrow sense. Product

reliability at the user's site is called "reliability of use," which consists mainly of reliability in the broad sense. In the relay industry, reliability

of use has a significance in aspects of servicing.

[2] Reliability Measures

The following list contains some of the most popular reliability measures:

Reliability measure

Degree of reliability R(T)

MTBF

Sample representation

99.9%

100 hours

MTTF

100 hours

Failure rate lambda

Safe life B₁₀

20 fit, 1%/hour

50 hours

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1. Degree of Reliability

Degree of reliability represents percentage ratio of reliability. For example, if none of 10 light bulbs has failed for 100 hours, the degree of

reliability defined in, 100 hours of time is 10/10 = 100%. If only three bulbs remained alive, the degree of reliability is 3/10 = 30%. The JIS

Z8115 standard defines the degree of reliability as follows: The probability at which a system, equipment, or part provides the specified

functions over the intended duration under the specified conditions.

2. MTBF

MTBF is an acronym of Mean Time Between Failures. It indicates the mean time period in which a system, equipment, or part operates

normally between two incidences of repair. MTBF only applies to repairable products.

MTBF tells how long a product can be used without the need for repair.

Sometimes MTBF is used to represent the service lifetime before failure.

3. MTTF

MTTF is an acronym of Mean Time To Failure. It indicates the mean time period until a product becomes faulty MTTF normally applies to

unrepairable products such as parts and materials.

The relay is one of such objective of MTTF.

4. Failure Rate

Failure rate includes mean failure rate and momentary failure rate. Mean failure rate is defined as follows:

Mean failure rate = Total failure count/total operating hours

In general, failure rate refers to momentary failure rate. This represents the probability at which a system, equipment, or part, which has

continued normal operation to a certain point of time, becomes faulty in the subsequent specified time period.

Failure rate is often represented in the unit of percent/hours. For parts with low failure rates, "failure unit (Fit) = 10^-９/hour" is often used

instead of failure rate. Percent/count is normally used for relays.

5. Safe Life

Safe life is an inverse of degree of reliability. It is given as value B which makes the following equation true:

1 - R(B) = t%

In general, "B[1 - R(B)] = 10%" is more often used. In some cases this represents a more practical value of reliability than MTTF.

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[3] Failure

1. What is Failure?

Failure is defined as a state of system, equipment, or component in which part of all of its functions are impaired or lost.

2. Bathtub Curve

Product's failure rate throughout its lifetime is depicted as a bathtub curve, as shown below. Failure rate is high at the beginning and end of

its service lifetime.

(I)

Initial failure period

The high failure rate in the initial failure period is derived from latent design errors, process errors, and many other causes.. This

process is called debugging, performing aging or screening in order to find out initial failures.

(II)

Accidental failure period

The initial failure period is followed by a long period with low, stable failure rate. In this period, called accidental failure period,

failures occurs at random along the time axis. While zero accidental failure rate is desirable, this is actually not practical in the real

world.

(III)

Wear-out failure period

In the final stage of the product's service lifetime comes the wear-out failure period, in which the life of the product expires due to

wear of fatigue. Preventive maintenance is effective for this type of failure. The timing of a relay's wear-out failure can be predicted

with a certain accuracy from the past record of uses. The use of a relay is intended only in the accidental failure period, and this

period virtually represents the service lifetime of the relay.

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3. Weibull Analysis

Weibull analysis is often used for classifying a product's failure patterns and to determine its lifetime.

Weibull distribution is expressed by the following equation:

where

Weibull distribution can be adopted to the actual failure rate distribution if the three variables above are estimated.

The Weibull probability chart is a simpler alternative of complex calculation formulas. The chart provides the following advantages:

(1) The Weibull distribution has the closest proximity to the actual failure rate distribution.

(2) The Weibull probability chart is easy to use.

(3) Different types of failures can be identified on the chart.

The following describes the correlation with the bathtub curve. The value of the parameter "m" represents the type of the failure.

(1) When m < 1

(2) When m = 1

(3) When m > 1

Initial failures

Accidental failures

Wear-out failures

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Product name:

Relay name:

Date:

Check sheet (1/2)

Refer to the following

page and item on

Page / Category -

Section

Check

box